1. Field of the Invention
This invention relates to a body for a vibrating grinding tool for grinding working surfaces, in particular wood surfaces. The grinding tool body is comprised of a support part carrying grinding material, the support part being movable relative to the working surface and having suction ducts ending on a working side for vacuuming off the grinding dust by means of an external suction system.
2. Description of the Prior Art
In grinding operations, particularly in the timber-processing industry, grinding dust is collected in substantial quantities. According to recent findings, grinding dust, especially of beech and oak timber, may be hazardous to the health. For this reason, applicable legal regulations specify that grinding dust released into the air is not to exceed predetermined quantities, for example, 5 mg per cubic meter of air, within the area of a work station. Such values could be attained, until now, only with stationary grinding machines and tools, because such machines and tools can be constructed in a manner whereby they are completely encapsulated. However, a substantial portion of the grinding work performed is done by hand. This work is performed manually, either with manually guided grinding tools, in particular vibrating grinding tools, or by moving the workpiece to be ground relative to a grinding tool. In such manual grinding operations, in which the grinding tool and the workpiece move relative to each other, grinding dust is always produced at different points, i.e., where the workpiece is being ground at a given moment. As complete encapsulation with suction hoods is not possible in manual grinding operations, the release of grinding dust cannot be avoided. Consequently, a mixture of air and grinding dust spreads out around the work station and cannot be adequately entrapped, even with the most powerful suction systems.
It is well known to equip grinding tools used in manual grinding, in particular vibrating grinding devices, with bodies having a part supporting the grinding material. The latter is usually a grinding sheet, which is applied to the working side of the support part. The working side of the body is fitted with bores serving as suction ducts, and the grinding sheet has holes formed therein which, when the grinding sheet is applied to the working side of the body, are aligned with and cover the bores in the support part. The bores in the support part serve as suction ducts connectable with an external suction system. This suction system vacuums away the grinding dust produced during grinding via the holes in the grinding sheet and via the bores of the support part, and then discharges such dust.
It has been found that the suction performance during grinding with the prior art grinding tool bodies is non-existent, or at least only minimal, because during grinding, the grinding sheet rests on the workpiece. This means that the workpiece practically covers the holes in the grinding sheet and consequently also covers the bores in the support part serving as the suction ducts. In grinding operations with these conventional grinding tool bodies equipped with vacuum grinding dust systems, no current of air that could carry along the grinding dust is produced.